Fix build

cmd/app.go

@@ -3,11 +3,12 @@ package cmd
 
 import (
 	"fmt"
+	"os"
+	"regexp"
+
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/altsrc"
 	"heckel.io/ntfy/v2/log"
-	"os"
-	"regexp"
 )
 
 const (
@@ -15,6 +16,12 @@ const (
 	categoryServer = "Server commands"
 )
 
+// Build metadata keys for app.Metadata
+const (
+	MetadataKeyCommit = "commit"
+	MetadataKeyDate   = "date"
+)
+
 var commands = make([]*cli.Command, 0)
 
 var flagsDefault = []cli.Flag{